Correlated set of clubs with indicator line

ABSTRACT

In a correlated set of golf clubs at least one visible indicator line on the striking face of each club head is provided. This indicator line lies in the loft plane of the club head and is in a predetermined angular relationship with a second line, real or imaginary, and being perpendicular to a third line, real or imaginary, formed by the intersection of the loft plane and the plane on which the club is placed in its normal position for striking a golf ball. The angular relationship is a certain degree for each successive club in the set.

finite States ateiat 1 1 Cochran et a1.

1 1 Mar. 27, 1973 1 CORRELATED SET OF CLUS WITH INDICATOR LINE [75]inventors: Alastair J. Cochran, Sutton, Coldfield, England; John W.Jepson, Marion, Mass; Edward R. Woolle'y, Rancho Santa Fe, Calif.;Francis deS. Lynch, Mattapoisett, Mass.

[58] Field-of Search ....273/77 A, 163 R, 163 A, 164, 273/167 R, 167 J,183 D [56] References Cited UNITED STATES PATENTS 1,569,212 H1926 Aitken..273/l64 7/1934 Davis Primary ExaminerRichard C. Pinkham AssistantExaminer-Richard .l. Apley Attbrney-Eyre, Mann & Lucas [57] ABSTRACT Inacorrelated set of golf clubs at least one visible indicator line on thestriking face of each club head is provided. This indicator line lies inthe loft plane of the club head and is in a predetermined angularrelationship with a second line, real or imaginary, and beingperpendicular to a third line, real or imaginary, formed by theintersection of the loft plane and the plane on which the club is placedin its normal position for striking a golf ball. The angularrelationship is a certain degree for each successive club in the set.

5 Claims, 6 Drawing Figures PATEMEUHARZYISTS 3,722,887 I SHEET 18? 2PATEHTEULRRZYUYS SHEET 2 U? 2 CORRELATED SET OF CLUBS WITH INDICATORLINE The present invention is a division of our co-pending applicationSer. No. 146,255 filed May 24, i971 and is an improvement on ourc'o-pending application Ser. No. 106,690 filed Jan. 15,1971.

In our latter co-pending application we broadly disclose the manner inwhich the sweet spot of a golf club head can be enlarged by moving theweight of the club head towards the heel and the toe.

It has been found that protrusions on the back of the club head whichare visible to the golfer tend to distract the golfer and divert hisattention so that he does not concentrate completely on the shot to bemade. We have now discovered. that an improved golf club can be madeincorporating the advantages of our prior invention and having a furtheradvantage of not having the back of the club head visible to the golferso that it is not distracting to the golfer. The means for accomplishingthis is by hollowing out a substantial portion of the back of the clubhead directly behind the scored part of the face and adding weights inthe area of the heel and the toe, as close to the heel and the toe aspossible. One or more reinforcing members are preferably located Iacross the hollowed out back of the clubhead.

We have also discovered that there is advantage in having indicatorlines on the face of the clubs at an increasing angle for eachsuccessive club in relation to a line lying in the loft plane of theclub head and being perpendicular to the line formed by the intersectionof the loft plane and the plane on which the club is placed in itsnormal position for striking a golf ball. The loft .club head face.Standard golf clubs have indicator lines near the edges of the scoredarea essentially along this line for each club. We have discovered thatif the indicator lines (or other linear markings) are at an angle withrelation to this line and with the angle increasing by approximately foreach club from the 9 iron to the 2 iron, then it is easier to line upthe club head with the ball for the proper shot.

These and other advantages of the present invention may be .more fullyunderstood with reference to the accompanying drawings in which likenumbers are used for like parts and wherein:

FIG. 1 shows a golf club made in accordance with the present inventionin use by a golfer;

FIG. 2 shows the back of the club head made in accordance with thepresent invention;

FIG. 3 shows a sectional view of FIG. 2 taken through line 2--2; I

FIG. 4 shows a golfer in standard position for addressing a golf ballusing a golf club with the unique indicator lines of the presentinvention;

FIG. 5 shows the face on a golf club with the indicator lines of thepresent invention; and

FIG. 6 shows a series of golf clubs with the indicator lines increasingin angle according to the present invention.

In FIG. 1 there is shown a golfer 10 holding a golf club 12 in standardposition for striking a golf ball l4.

The golf club 12 has a club head 16 made in accordance with the presentinvention. The line of sight 18 of the golfer l0 sees the back of thetop of the club head 20 but does not see any portion of the back of theclub head 22. The reason for this is that the entire back 22 of the clubhead 16 is on one side of a plane 24 which is parallel to the axis ofthe club shaft 26 and is tangential to the top of the club head 20.Since there are no protrusions on the back of the club head, thegolfer's eye is not distracted when addressing the ball in standardposition. For purposes of the present invention, the back of the clubhead is defined as that part of the back of the club head which is belowthe top 27 of the club head.

FIG. 2 shows the back of the golf club head of FIG. 1. There is providedan upper hollowed out area 28 and a lower hollowed out area 29 whichcomprise a substantial portion of the back of the club head definedby'an area corresponding to the edges of the scored area 30 and 32. Thetop of the club head 20 to which plane 24 of FIG. I is tangential may bedefined by the line along the top of the club head extending from line30 to line 32. One or more reinforcing ribs 34 are preferably located inthe hollowed out areas 28 and 29 in order to reinforce the club head. Ina preferred embodiment of the invention, and as shown, the center line36 of the rib 34'essentially bisects'the angle 0 made by a line 38passing through the back of the top of the club 20 and a line 40 passingthrough the back of the bottom of the lower hollowed'out area 29. Whenthe center of the rib is located along this line, it is highlyadvantageous since this is the area in which most golf balls are struckand thus the reinforcing rib reinforces the golf club head at the placewhere greatest stress is put upon it. While this is the preferredlocation for the reinforcing rib, it is to be understood that thereinforcing rib could be in an X shape in which case there could be fourhollowed out areas or in any other desired shape or there could be norib at all. The only requirement is that theclub head be strongenou'ghto preserve its structural integrity under normal playingconditions.

Weights 44 and 46 are shown located in'the heel and the toe of the clubhead respectively. These weights are made of a material which is moredense than the material of which the club head 16 is made. It has beenfound that for best results there should be a weight in the toe in orderto make a golf club wherein all of the club head is confined within thearea defined by a plane which is parallel to the axis of the shaft 26and tangential to the back of the top of the club 20 and it ispreferable that a heel weight 46 be provided. While the heel weight isshown on the back of the club head, it is to be understood that thisheel weight can be located in the bottom 48 of the hosel shaft receivinghole 50. For maximum benefit the weights 44 and 46 should be located asclose as practical to the toe 52 and heel 54. The center of mass of theclub head is preferably located at a point 56 which is equidistantbetween lines 30 and 32. In order to locate the center of mass at thispoint, and still maintain the other desirable features of the presentinvention, the mass of the weight 44 located in the toe area should beat least three times as great as the mass of the weight 46 added in theheel area. The weights 44 and 46 are preferably made of tungsten alloysand for best results the tungsten alloyed weights should contain betweenabout 85 and 95 percent tungsten. If the percentage of tungsten isgreater than about 95 percent the weights become brittle and are noteasily fabricated. On the other hand, if the percentage of tungsten isless than about 85 percent, then there is little advantage since themass of the tungsten alloy will not be sufficiently greater than themass of the club head material, which is usually iron or stainlesssteel.

In all cases, club heads according to the present invention have aradius of gyration above about 1.05 inches about an axis which isparallel'to the shaft and which passes through the centroid (center ofmass) of the club head. A suitable method for measuring this radius ofgyration is set forth in our prior co-pending application referred tohereinabove. The radius of gyration can be defined by the followingformula:

K= Vl/M wherein K is the radius of gyration about a specific axis, I isthe moment of inertia of the club head about the same axis and M is theinass of the club head. Theclub head is defined as the weight of a golf.club below a point located about inches up the golf club shaft from theheel. In determining the moment of inertia of the club head, thecentroid (center of mass) of the club head is first located in knownmanner. A point is then selected along an axis which passes through thecentroid of the club head and is parallel to the axis of the gold clubshaft. The club head is suspended from this point by one or more wiresor other suitable means which maintain the club head parallel to theaxis of the shaft. The moment of inertia of the club head is thendetermined in known manner with respect to the axis which passes throughthe centroid. When the moment of inertia is thus determined and the massof the club head is determined, the radius of gyration can be computedaccording to the formula given hereinabove.

It has-now been found that best results are achieved when the radius ofgyration of the club head for each of the 2 through 9 irons is withinthe ranges as set out in the Table below.

TABLE Minimum Radius Maximum Radius of Gyration of Gyration IRON(inches) (inches) 2 1.06 1.17 3 1.07 1.18 4 1.08 1.19 5 1.09 1.20 6 1.101.21 7 1.1 1 1.22 8 1.12 1.23 9 1.13 1.24

If a wedge is to be included in the set, it will preferably have aradius of gyration from about 1.14 to about 1.25 inches. The weight ofthe club head will generally be the same as conventional club heads.This will generally be from about 4 to about 12 ounces for the 2 ironand from about 6 to about 16 ounces for the 9 iron and best results areobtained with a club head weight of from about 8 to about 9 ounces for a2 iron and from about to about 1 1 ounces for the 9 iron with the restof the clubs having a weight therebetween, the weight of each successiveclub increasing from the 2 iron to the 9 iron.

In FIG. 3 is shown a sectional view of FIG. 2 taken through line 3-3. Asthere shown, rib 34 extends through hollowed out areas 28 and 29essentially in the middle of the club head face 58. Plane 24 is showntangential to the top of the back of the club head 20 and parallel tothe shaft 26. The thickness of the club head face at points 60 and 62 ispreferably at least about 0.15 inches since otherwise there may be anundesirable pinging sound when the club makes contact with the ball.

In FIG. 4 there is shown a side view of a golfer addressing a golf ballwith a golf club having a club head face made in accordance with thepresent invention. As there shown, the indicator lines 72,74 areparallel to the edges 30 and 32 of the scored area of the club head andare on an angle so that they appear approximately straight with the lineof sight l8'of the golfer 10. In present day clubs, the indicator lines72 and 74 are substantially perpendicular to the line 64 formed by theintersection of the loft plane and the plane on which the club head isplaced in its normal position for striking a golf ball. The golfer,however, looks down at the club at an angle a from the perpendicular 66.Because of this, the indicator lines 72 and 74 appear to be fallingaway" from the golfer and this makes it somewhat difficult to line up ashot. It has been found that if these lines 72 and 74 are set at anangle B which appears to the golfer to correspond approximately to hisline of sight 18, then the lines 72 and 74 will appear to be parallel tothe line of flight along which it is intended to hit the golf ball.Because of variations in length of shaft and in the angle of loft ofclub head faces, this angle will not be the same for every club from the2 through the 9. In addition, lines 72 and 74 may not appear tocorrespond exactly to the line of sight 18 of the golfer 10 because ofvarying heights and stances of golf players. However, even though theindicator lines do not appear to correspond exactly with the line ofsight of the golfer, it has been found that when they are made inaccordance with the present invention it is considerably easier for thegolfer to line up his shot. The greatest change in angle [3 is requiredfor the 2 iron and the least change in angle is required for the 9 iron.It

has been found that the difference in angles from the 9 to the 8, fromthe 8 to the 7 and so on through the 2 should be from about 14 to about94 for each successive club and preferably the increase in angle shouldbe about h". For example, in accordance with the preferred angle, if the9 iron has an angle )3 of 0, then the 8 iron will have an angle of 15,the 7 iron will have an angle of 1, the 6 iron will have an angle of 1%,the 5 iron will have an angle of 2 degrees, the 4 iron will have anangle of 256, the 3 iron will have an angle of 3 and the 2 iron willhave an angle of 3%. It is preferred that the 9 iron have an angle ofabout 3 and that the angle of the indicator lines of the rest of theclubs increase to an angle of about 6 6 for the 2 iron. While thedescription of the indicator lines has been given with respect to acomplete set of 2 through 9 irons, it I will be understood that it hasequal applicability to socalled beginner sets" which usually comprisethe 3, 5, 7 and 9 irons. In such a set the increase angle would bedoubled i.e., it would be W to 156 greater for each club than theimmediately preceding club and the angle is preferably 1 greater. Thus,if the 9 iron has an angle of the 7 iron will have an angle of 1, theiron an angle of 2 and the 3 iron an angle of 3. It will be understoodthat when the term angle is used, it is intended to mean the angleformed by an indicator line 72, 74 and a line 68 lying in the loft planeof the club head and being perpendicular to the line 64 formed by theintersection of the loft plane and the plane on which the club is placedin its normal position for striking a golfball.

In FIG. 5 there is shown a face of a golf club comprising a scored area70 with grooves 71, edges of the scored area 30 and 32 and indicatorlines 72 and 74. The indicator lines 72 and 74 are at an angle B withrespect to line 68. The edges 30 and 32 of the scored area 70 may be atthe same angle as lines 72 and 74 or they may be parallel to line 68 asshown. In the preferred embodiment of the present invention, lines 72and 74 are coincident with lines 30 and 32 and are at an angle withrespect to line 68 as previously discussed. It will be understood thatwhen the term line" is used with reference to lines 30, 32, 72 and 74,it is intended to include a single unbroken line as well as a series ofdots, diamonds, maltese crosses or other configurations which are in aline.

In FIG. 6 is shown a correlated set of clubs having the indicator lines72 and 74 of the present invention. The 9 ironis shown at the top ofFIG. 6 and the 2 iron is at the bottom. Each successive club has anincrease in the angle B from 54 to 34 over the next preceding club andthe angle [3 of the 9 iron is anywhere from 06, depending upon thelength of the shaft of the club, the loft of the club and'the height ofthe golfer for which the club is intended.

It will be understood that the claims are intended to cover all changesand modifications of the preferred embodiments of the invention, hereinchosen for the purpose of illustration, which do not constitutedepartures from the spirit and scope of the invention.

What is claimed is:

1. In a correlated set of golf clubs comprising the 2, 3, 4, 5, 6, 7, 8and 9 irons, the improvement which comprises at least one visibleindicator line on the striking face of each club head, said indicatorline lying in the loft plane of the club head and in a predeterminedangular relationship with a second line, real or imaginary, lying in theloft plane of the club head and being perpendicular to a third line,real or imaginary, formed by the intersection of the loft plane and theplane on which the club is placed in its normal position for striking agolf ball, said angular relationship being from about 0 to about 6 for a9 iron and from about to about 34 greater for each successive club inthe set.

2. The set of clubs of claim 1 wherein the said angular relationship ofthe indicator line in each successive club is about 56 greater than eachpreceding club.

3. The set of clubs of claim 1 in which the said angular relationship ofthe indicator line of the 9 iron is about 0, the said angularrelationship of the indicator line of the 8 iron is about 96, the saidangular relationship of the indicator line of the 7 iron is about 1, thesaid angular relationship of the indicator line of the 6 iron is about1%", the said angular relationship of the indicator line of the 5 ironis about 2, the said angular relationship of the indicator line of the 4iron is about 2%, the said an ular relationship of the indicator line ofthe 3 iron IS a out 3 and the said angular relationship of the indicatorline of the 2 iron is about 3%.

4. In a correlated set of golf clubs comprising the 3, 5, 7 and 9 irons,the improvement which comprises at least one visible indicator line onthe striking face of each club head, said indicator line lying in theloft plane of the club head and in a predetermined angular relationshipwith a second line, real or imaginary, lying in the loft plane of theclub head and being perpendicular to a third line real or imaginaryformed by the intersection of the loft plane and the plane on which theclub is placed in its normal position for striking a golf ball, saidangular relationship being from about W to about 1% greater for eachsuccessive club in the set.

5. The set of clubs of claim 4 wherein the said angular relationship ofthe indicator line in each successive club is about 1 greater than eachpreceding club.

1. In a correlated set of golf clubs comprising the 2, 3, 4, 5, 6, 7, 8and 9 irons, the improvement which comprises at least one visibleindicator line on the striking face of each club head, said indicatorline lying in the loft plane of the club head and in a predeterminedangular relationship with a second line, real or imaginary, lying in theloft plane of the club head and being perpendicular to a third line,real or imaginary, formed by the intersection of the loft plane and theplane on which the club is placed in its normal position for striking agolf ball, said angular relationship being from about 0* to about 6* fora 9 iron and from about to about 3/4 * greater for each successive clubin the set.
 2. The set of clubs of claim 1 wherein the said angularrelationship of the indicator line in each successive club is about1/2 * greater than each preceding club.
 3. The set of clubs of claim 1in which the said angular relationship of the indicator line of the 9iron is about 0*, the said angular relationship of the indicator line ofthe 8 iron is about 1/2 *, the said angular relationship of theindicator line of the 7 iron is about 1*, the said angular relationshipof the indicator line of the 6 iron is about 1 1/2 *, the said angularrelationship of the indicator line of the 5 iron is about 2*, the saidangular relationship of the indicator line of the 4 iron is about 2 1/2*, the said angular relationship of the indicator line of the 3 iron isabout 3* and the said angular relationship of the indicator line of the2 iron is about 3 1/2 *.
 4. In a correlated set of golf clubs comprisingthe 3, 5, 7 and 9 irons, the improvement which comprises at least onevisible indicator line on the striking face of each club head, saidindicator line lying in the loft plane of the club head and in apredetermined angular relationship with a second line, real orimaginary, lying in the loft plane of the club head and beingperpendicular to a third line real or imaginary formed by theintersection of the loft plane and the plane on which the club is placedin its normal position for striking a golf ball, said angularrelationship being from about 1/2 * to about 1 1/2 * greater for eachsuccessive club in the set.
 5. The set of clubs of claim 4 wherein thesaid angular relationship of the indicator line in each successive clubis about 1* greater than each preceding club.